1. Field of the Invention
This invention relates to a processing system utilizing a multi-purpose motion picture film handling cartridge permitting the photographer himself to process and project the film strip easily and without failure. More particularly, it relates to a variable-speed driving mechanism adapted for association with externally mounted drive means of the cartridge to impart a constant speed to the film strip as it is transported across a processing station positioned within the cartridge.
2. Description of the Prior Art
The field of amatueur motion picture photography has developed rapid processing and projection systems utilizing compact multi-purpose film handling cartridges. The film handling cartridge is adapted to be mounted first in a motion picture camera for exposure purposes and then in a motion picture projector for projection purposes. After a strip of photographic motion picture film contained in the cartridge has been exposed, the film strip is processed with the cartridge remaining unremoved from the same camera employing a rapid processing system, or mounted in a specially designed processor, or in a processor-projector unit which is constructed for facilitating processing and projection operations. In these systems, the processing fluid is stored in an applicator positioned within the cartridge from which it is expressed onto the exposed film strip when the processing station is rendered operable. Examplary of such systems are those described in U.S. Pat. Nos. 3,644,024 and 3,604,790.
In applying a thin coating of processing fluid to an exposed strip of motion picture film contained in the cartridge, it is of importance to maintain constant the rate of travel of the film strip as it contacts the applicator, or otherwise uniform processing results can not be effected particularly when the exposed film is processed not in a processing laboratory but in the aforesaid rapid processing system employed in a camera projector, or a handy processor specially designed therefor. The presently proposed variable-speed driving mechanisms adapted for use in such rapid processing systems to impart a constant speed to the film strip as it contacts the applicator are described in U.S. Pat. Nos. 3,616,740 and 3,623,417. The variable speed driving mechanism disclosed herein is associated with a specially designed applicator to control the speed of a drive motor incorporated therein in accordance with the amount of processing fluid remaining in the applicator as it is expelled from the orifice of the applicator.